boot loader (boot manager)

What is a boot loader (boot manager)?

A boot loader (boot manager) is a small program that places the operating system (OS) of a computer into memory. When a computer powers up or restarts, the BIOS performs some initial tests and then transfers control to the master boot record, where the boot loader resides. Most new computers ship with boot loaders for some version of Windows or macOS.

For Linux, the two most common boot loaders are known as Linux Loader (LILO) and Grand Unified Bootloader (GRUB), used with Red Hat Linux. LILO is the most popular boot loader among computer users that employ Linux as the main, or only, OS. LILO enables fast bootup. GRUB is preferred by many users of Red Hat Linux as it is the default boot loader for that distribution.